In conventional processes for manufacturing a pneumatic tire, a formed green tire is moved to a vulcanization device and placed in a mold attached to the vulcanization device. In the mold, a cylindrical vulcanization bladder is inserted in the green tire and inflated to a predetermined vulcanization internal pressure. As a result, the green tire is pressed against the mold while being heated at a predetermined temperature, thus vulcanizing the green tire. When the green tire is placed in the mold, if the green tire is not positioned in the mold in a preset position with high precision, after vulcanization, the uniformity of the manufactured pneumatic tire may be adversely affected.
However, a mold attached to a vulcanization device is subject to spatial restrictions. These restrictions prevent precision positioning of the green tire and confirmation of whether the position is suitable from being easy to perform. A method of vulcanizing a green tire is known in which a building drum on which a green tire is formed and the green tire are transported to a vulcanization device and placed in a vulcanization mold, and a bladder provided in the building drum is used to vulcanize the green tire (Japanese Unexamined Patent Application Publication No. 2012-86487A). In the method of vulcanization described in Japanese Unexamined Patent Application Publication No. 2012-86487A, the engagement between a central shaft of the building drum for supporting the green tire and a support hole formed in the vulcanization device into which the central shaft is insert, for example, can be rendered with high precision by machining, and as such is comparatively easy to achieve.
Accordingly, highly precise positioning of the green tire in the mold in a preset position can be realized by improving the precision with which the green tire, which is supported by the bladder provided in the building drum, is positioned with respect to the building drum (vulcanization bladder) outside of the vulcanization device before being placed in the mold attached to the vulcanization device. In regards to this, the present inventors conducted research and discovered the present technology, which is capable of positioning a green tire in a mold with high precision.